class Solution { private: const int kmod = 1000000007; public: void merge_sort__(vector<int>& arr, vector<int>& tmp, int l, int r, int& ret) { if(l>=r) { return; } int mid = (r+l)/2; // 二分后 再分别 divide merge_sort__(arr, tmp, l, mid, ret); merge_sort__(arr, tmp, mid+1, r, ret); // 分完之后的...